液/固体系中硅藻土对Pb^(2+)和Cd^(2+)的吸附机制  

Adsorption mechanism of Pb^(2+) and Cd^(2+) on diatomite in liquid/solid systems

作　　者：朱健 王平[1] 雷明婧[1] 张烨[1] 张伟丽[1] 

机构地区：[1]中南林业科技大学环境科学与工程研究中心,长沙410004

出　　处：《环境工程学报》2012年第11期4123-4128,共6页Chinese Journal of Environmental Engineering

基　　金：湖南省自然科学省市联合基金资助项目(12JJ8016);环保公益性行业科研专项(200909066);湖南省环境科学重点学科建设基金资助项目(2006180)

摘　　要：为了提高硅藻土在重金属废水处理上的应用水平,采用静态吸附实验考察了液/固体系中硅藻土对Pb2+、Cd2+的吸附影响因素、吸附等温线和吸附动力学属性。结果表明,随着投加量的减少,离子初始浓度的提高,pH值的增大,吸附作用时间的延长,硅藻土对Pb2+、Cd2+吸附量不断上升;硅藻土对Pb2+、Cd2+的等温吸附都符合Langmuir模型,硅藻土对Pb2+、Cd2+最大吸附量分别为10.428 mg/g和7.916 mg/g,硅藻土对Pb2+具有更好的吸附能力;Pb2+具有较低的水合自由能,更容易脱去水膜与硅藻土孔道内的活性基团发生吸附作用;双常数扩散方程可以很好地描述硅藻土对Pb2+、Cd2+的吸附动力学属性,硅藻土对Cd2+有较快的吸附速率。In order to promote application levels of diatomite in treatment of wastewater containing heavy metals,adsorption influencing factors,isotherms,kinetics of Pb2＋ and Cd2＋ on diatomite were studied by static adsorption experiment in liquid/solid systems.The results showed that adsorption quantity of Pb2＋ and Cd2＋ on diatomite will enlarge as decrease of diatomite dose and increase of ion initial concentration,pH,adsorption time.Adsorption isotherms of Pb2＋ and Cd2＋ on diatomite were both consistent with Langmuir model.The maximum adsorption quantities of Pb2＋ and Cd2＋ were 10.428 mg/g and 7.916 mg/g,respectively.The adsorption property of Pb2＋ on diatomite was better.Hydration energy of Pb2＋ was lower,so Pb2＋ can take off water film smoothly,and get into diatomite channels to react with active groups easily.Two-constant equation can indicate adsorption kinetics of Pb2＋ and Cd2＋ on diatomite well,adsorption rate of Cd2＋ on diatomite is higher.

关 键 词：硅藻土 PB2+ Cd2+ 吸附影响因素 吸附等温线 吸附动力学 

分 类 号：X703[环境科学与工程—环境工程]